Abstract: The predicted error of the particle blasting vibration velocity by using Sadovsky formula can be up to 200%~300% in medium or near blasting zone，which is not conducive to the accurate prediction of the blasting vibration velocity in medium or near blasting zone.The phenomenon of the rock fall and radial crack propagation caused by the tensile failure of the near-zone compression stress wave in the blasting is more obvious，and these tensile failure phenomena accelerate the decay process of the blasting vibration speed to a certain extent.In order to study the influence of rock mass tensile strength to the attenuation of blasting vibration velocity in medium or near blasting zone，based on the analysis of the existing attenuation formulas of blasting vibration velocity both at home and abroad，14 influence factors of peak blasting vibration velocity are discussed，and dimensional analysis are conducted by selecting 9 main factors of them.By considering the tensile strength of quasi-rock mass，the improved blasting vibration velocity attenuation formula is derived.Based on the engineering example of an open-pit iron mine，by using 1st0pt software，multivariate nonlinear regression analysis for the improved attenuation formula and Sadovsky formula are done respectively.The study results show that the average relative prediction error of the particle blasting vibration velocity based on the improved attenuation formula is 8.41% and 7.01% of the south and north area of the mining area，which are higher than the ones of the traditional attenuation formula.The improved attenuation formula can provide the reliable reference for the blasting operation of open-pit mine.

Key words: Open-pit mining, Attenuation of blasting vibration velocity, Tensile strength of quasi-rock mass, Sadovsky formula, Dimensional analysis, Multivariate nonlinear regression